Bi-component staple or short-cut trilobal fibres and their uses

ABSTRACT

A bi-component staple or short-cut fibre includes a core and a sheath, the sheath and the core have different melting points, with the sheath melting point being lower than the core melting point, the bi-component fibre having an outer trilobal shaped cross-section. The core of the bi-component fibre can have a cross-section whereby the outer trilobal shaped cross-section is created by a conformal layer of sheath material applied to the core. 
     The fibres can be used, in dry or wet wipes, absorbent articles, hygiene products, filters, carpets, rugs or mats, etc.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a U.S. National Phase Patent Application ofPCT Application No.: PCT/EP2017/060246, filed Apr. 28, 2017, whichclaims priority to European Patent Application No.: 16167771.1, filedApr. 29, 2016 and European Patent Application No.: 16195024.1, filedOct. 21, 2016, each of which is incorporated by reference herein in itsentirety.

FIELD OF THE INVENTION

The present invention relates generally to shaped bi-component fibresand their manufacture, textiles made with these bi-component fibres andtheir manufacture, more particularly, to nonwovens made with thesebi-component fibres and their manufacture and products made with thenonwovens and their manufacture. The present invention also relates inone aspect to the improved bonding properties of a bi-component fibrewith a trilobal shape, suitable for the preparation of staple andshort-cut fibres and nonwoven fabrics having superior softness.

BACKGROUND OF THE INVENTION

In recent years, the market of bi-component fibres, to be used as abinding agent in nonwovens, has grown significantly mainly because thesesystems, having a higher melting point core and a lower melting pointsheath, have shown a series of advantages over mono-component “binder”fibres in several applications. However, shaped bi-component fibres areconsidered to increase costs so that the extra costs can outweigh anybenefits.

The demand of the hygiene market for lighter and softer products is alsocontinuously growing. In this context, nonwovens can be produced byusing conventional bi-component fibres with round cross-sections andbased on polyolefin polymers. For instance, a standard sheath/corebi-component fibre in which the round core is made of 50% by weight ofpolypropylene (with a density of about 0.91 g/cm³ and a meltingtemperature of around 165° C.) and a concentric sheath is made of a 50%by weight of polyethylene (with a density of about 0.95 g/cm³ and amelting temperature of around 130° C.) allows the formation of bondingspots at temperatures that lie between the melting temperatures of thetwo core and sheath polyolefins. Moreover, the polyethylene of theexternal sheath can lead to an excellent bondability of the fibrestogether with an excellent softness of the obtained nonwoven, whereasthe polypropylene in the core can assure that the nonwoven structuremaintains a suitable mechanical consistency even after a thermaltreatment able to generate the bonding spots.

Bonding fibres are mentioned in several patents: U.S. Pat. Nos.9,108,839, 8,487,026, 7,959,751, 7,695,660, 7,309,522, 6,916,752,6,911,174, 4,123,577, 4,087,507 and 3,322,607. In particular, in U.S.Pat. No. 9,108,839 a nonwoven is disclosed comprising three separate anddistinct fibres in which the thermoplastic fibres are mixed to create arandom laid layer. On the other hand, the U.S. Pat No. 7,959,751describes a process for producing a composite material having at leastone layer comprised of elements that are bonded together, the methodcomprising airlaying an assembly of one or more layers of randomlyoriented fibrous elements. This assembly contains a thermoplasticthermally sensitive bonding fibre capable of bonding with othermaterials in the assembly during activation.

A nonwoven liner for a disposable diaper having improved softness,tensile strength, and moisture transfer capability is described in theU.S. Pat. No. 4,668,566, in which at least two layers of nonwoven websare adjacent and bonded to each other. Each nonwoven web comprises aplurality of monofilaments or fibres of a thermoplastic material. In oneof the webs the monofilaments or fibres are made from polypropylene. Inanother of the webs the monofilaments or fibres are made frompolyethylene. It is said that this nonwoven provides remarkablyincreased softness and tensile strength as well as other desirableproperties.

Multicomponent fibres are also mentioned in the U.S. Pat. Nos.5,108,820, 5,336,552, 5,382,400, in which for two component fibres orfilaments, the polymers may be present in ratios of 75/25, 50/50, 25/75or any other desired ratios.

On the other hand, to obtain properties such as opacity, barrierproperties and liquids management with mono-component fibres basednonwovens, shaped fibres can be in used. For instance, as described inthe U.S. Pat. No. 5,607,766 and EP0881889, sheath-core bi-componentfibres comprising a core of a thermoplastic material (preferablypolypropylene or polybutylene terephthalate) are completely covered witha sheath formed of polyethylene terephthalate or a copolymer. Theyexhibit interesting properties useful in various applications, such asink reservoir elements for a marking or writing instrument, although theporous element may also find utility as a tobacco smoke filter. Otherforms of the same product have utility in other applications where itsexcellent capillary, absorption and filtering properties areadvantageous.

The nonwoven disclosed in the U.S. Pat. Nos. 4,753,934 and 4,778,460comprises a plurality of fibres or monofilaments of a thermoplasticmaterial, each monofilament having a “bilobal” cross-section. By theterm “bilobal” the applicants intend to refer to a shape including anelongate substantially rectangular portion which has at each of itsfurthest separated ends an enlarged portion which is typically circularand which portion has a diameter greater than the thickness of therectangle. A nonwoven web made with such bilobal shaped monofilamentsresults in remarkably increased softness as well as other desirableproperties.

WO03049589 describes a cleaning sheet that has an enhanced dirt, dustand/or debris pick-up and retention characteristics. The cleaning sheetis prepared from a nonwoven web containing plurality of multicomponentmultilobal filaments, wherein the multicomponent multilobal filamentshave a plurality of raised lobal regions separated by depressed regions.The nonwoven web can be a single layer or a layer of a multilayerlaminate and could be optionally electret treated.

All the above mentioned patents exploit the benefits of themultilobality of the fibres to their surface performance due to theincreased of contact areas and improved capillarity properties.

Some nonwovens are produced by combining binder round fibre (useful toassure a suitable mechanical consistency of the web) with a shaped fibre(useful to improve the porosity and capillarity of the web) in order toexploit the main characteristics of both the systems. For instance, inthe WO2012127346 a method of making a resilient tampon is described byincluding 70 wt % to 95 wt % absorbent fibres (such as trilobal viscoserayon fibres) and 5 wt % to 30 wt % bi-component binder fibres. However,the need of using high percentages of a standard round bi-componentfibres (normally higher than a 50 wt %) to be used as binder agent toassure a suitable mechanical consistency of nonwovens (for instance madeby means of air-through bonding technology) represents a limit to theuse of shaped fibres in high percentage when necessary to reach somespecific properties.

SUMMARY OF THE INVENTION

The present invention relates to a bi-component staple or short-cutfibre with a trilobal shape, and optionally crimped, and itsmanufacture. Such a staple or short-cut trilobal, optionally crimped,fibre can be particularly suitable for the preparation of nonwovenfabrics. An advantage of embodiments of the present invention is thatnonwovens according to any of the embodiments of the present inventioncan have superior softness, and/or can have improved thermal-bondingproperties.

One aspect of the present invention relates to a bi-component staple orshort-cut, optionally crimped, fibre comprising a core and a sheath, thesheath and the core have different melting points, with the sheathmelting point being lower than the core melting point, the bi-componentstaple or short-cut, optionally crimped, fibre having an outer trilobalshaped cross-section. The core of the bi-component staple or short-cut,optionally crimped, fibre can have a cross-section whereby the outertrilobal shaped cross-section is created by a conformal layer of sheathmaterial applied to the core. The sheath material of a bi-component astaple or short-cut trilobal, optionally crimped, fibre is preferably aconformal coating on the shaped core fibre. A conformal layer is apolymeric layer which ‘conforms’ to the contours of the shaped core. Thelayer preferably has a constant thickness or a substantially constantthickness. Preferably there is at least a certain amount of sheathmaterial at each position on the surface of the core or preferably thereis at least a certain amount of sheath material at a position around anycircumference of the core

The core of the bi-component staple or short-cut, optionally crimped,fibre preferably has the same or similar symmetry as the sheath, i.e.the axes of the lobes of the trilobal outer shape radiate along threeangularly spaced directions, nominally with 120° between each axis. Thecore has a similar three point symmetry, e.g. is a delta shape, or atrilobal shape.

A polymer used for the sheath of a bi-component staple or short-cuttrilobal, optionally crimped, fibre can be a co-polyester, a polyolefin,or an olefin copolymer and a polymer used for the core is a polyolefinsuch as polypropylene (PP) or an olefin copolymer such as apolypropylene copolymer or a polyester or a co-polyester. In onepreferred embodiment, the polymer used for the sheath of a bi-componenta staple or short-cut trilobal, optionally crimped fibre, is apolyolefin selected from polypropylene, and polyethylene (LDPE, LLDPE orHDPE). In any of the embodiments a or the polymer used for the sheathcan comprise a non-grafted polyolefin component and a grafted polyolefincomponent, wherein the grafted polyolefin component is present in thesheath by at most 50%, preferably at most 30% and most preferably atmost 10%, by weight of the sheath. The grafting monomer may beethylenically unsaturated carboxylic acids and ethylenically unsaturatedcarboxylic acid anhydrides, including derivatives of such acids, andmixtures thereof, and vinyl trialkoxy silanes. Examples of the acids andanhydrides, which may be mono, di- or polycarboxylic acids, are acrylicacid, methacrylic acid, maleic acid, fumaric acid, itaconic acid,crotonic acid, itaconic anhydride, maleic anhydride and substitutedmaleic anhydride e.g. dimethyl maleic anhydride or citraconic anhydride,nadic anhydride, nadic methyl anhydride and tetrahydro phthalicanhydride. Examples of derivatives of the unsaturated acids are salts,imides, amides and esters e.g. mono- and disodium maleate, acrylamide,maleimide, glycidyl methacrylate and diethyl fumarate. Examples of thevinyl trialkoxy silanes are vinyl trimethoxy silane and vinyl triethoxysilane.

The sheath can represent from 10-90% 20-80%, or 30-70%, preferably from40-60%, even more preferably from 45-55% by weight of the bi-componentstaple or short-cut trilobal, optionally crimped, fibre. The core canrepresent from 90-10% 80-20%, or 70-30%, or 60-40%, or 55-45% by weightof the bi-component staple or short-cut trilobal, optionally crimped,fibre and the sheath has the remaining amounts.

For example, there can be 45-55% by weight (of the bi-component stapleor short-cut trilobal, optionally crimped, fibre) Polypropylene (PP) inthe core and 55-45% by weight (of the bi-component staple or short-cuttrilobal, optionally crimped, fibre) Polyethylene (PE) in the sheath.

The core can include between 10% and 90%, preferably between 20% and 80%by weight (of the bi-component staple or short-cut trilobal optionallycrimped fibre) of Polypropylene (PP) and the sheath can include between90% and 10%, preferably between 80% and 20% by weight (of thebi-component staple or short-cut trilobal, optionally crimped, fiber) ofPolyethylene (PE).

The bi-component staple or short-cut trilobal, optionally crimped, fibrecan have a final titre between 0.5 and 35 dtex, preferably for someapplications between 0.9 and 17 dtex or 0.9 and 9 dtex.

A nonwoven structure can include the bi-component staple trilobal,optionally crimped, fibres and be produced by carded thermal bonding,carded air-through bonding, spun bond, or is melt blown. The nonwovenstructure can be entangled e.g. by needle punching orhydro-entanglement.

A nonwoven structure can include bi-component short-cut trilobal fibresand can be produced by airlaying an assembly of one or more layers ofrandomly oriented fibres. The nonwoven structure of any of theembodiments of the present invention can have a basic weight between 10(or 12) gsm and 170 gsm for some applications or between 100 and 1000gsm for others.

In another embodiment an absorbent article can comprise a liquidpermeable body-facing cover layer, a liquid impermeable garment-facingbarrier layer and an absorbent core between the cover layer and thebarrier layer, the cover layer comprising the nonwoven structureaccording to any of the embodiments of the invention, e.g. a nonwovenstructure comprising bi-component staple or short-cut trilobal,optionally crimped, fibres.

An embodiment of the present invention also includes use of the nonwovenstructure according to any of the embodiments of the invention, e.g. anonwoven structure comprising bi-component staple or short-cut trilobal,optionally crimped, fibres as a surface sheet in absorbent articles.This use can be in absorbent articles that include beneath the surfacesheet an acquisition/transportation sheet and an absorbent sheet and aliquid-impermeable backing sheet. Any of these layers may include anonwoven structure comprising bi-component staple or short-cut trilobal,optionally crimped, fibres.

An embodiment of the invention includes the use of the nonwovenstructure according to any of the embodiments of the invention in afilter, e.g. a nonwoven structure comprising bi-component staple orshort-cut trilobal optionally crimped fibres.

An embodiment of the invention incudes the use of the nonwoven structureaccording to any of the embodiments of the invention in a carpet, rug ormat, or in upholstery e.g. a nonwoven structure comprising bi-componentstaple or short-cut trilobal, optionally crimped, fibres.

An embodiment of the invention incudes use of the nonwoven structureaccording to any of the embodiments of the invention in a dry or wetwipe.

For example, in one aspect the present invention an absorbent core, e.g.between a cover layer and a barrier layer, a surface sheet in absorbentarticles, a carpet, rug or mat, upholstery, dry or wet wipe, or filtersare provided comprising a nonwoven structure. The nonwoven structurecomprises shaped bi-component staple or short-cut trilobal, optionallycrimped, fibres bonded with themselves or with other bi-component fibresand/or with mono-component fibres. The bi-component staple or short-cuttrilobal, optionally crimped, fibres comprise a core and a sheath. Thesheath and the core have different melting points, with the sheathmelting point being lower than the core melting point. The bi-componentstaple or short-cut trilobal, optionally crimped, fibres have a shapedcross-section and preferably the bi-component fibres can retain theirshape after a thermo-welding process. To achieve this it is preferred ifthe outer shape is multi-lobal then the core should have the samesymmetry as the outer sheath. Hence it is preferred that if the outershape is trilobal and the core shape is preferably trilobal, or a deltashape. Hence the sheath is a concentric layer on the core.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the as spun PP/PE bicomponent/trilobal fibres according toan embodiment of the invention.

FIG. 2 shows the PP/PE bi-component/trilobal fibres (2.2 dtex) fibresaccording to an embodiment of the invention.

FIG. 3 shows the PP/PE bi-component/round fibres (2.2 dtex).

FIG. 4 shows an optical microscope magnification of a bonding spot.

FIG. 5 shows the typical configuration of the dynamometer during theexecution of the debonding tests.

FIG. 6 shows the debonding curves for the system PP/PE Bi-componentRound+PP Mono-component Round.

FIG. 7 shows the debonding curves for the system PP/PE Bi-componentTrilobal+PP Mono-component Round.

FIG. 8 includes TABLE A which shows the summary of the measureddebonding forces in centinewtons for the analysed systems.

FIGS. 9A to 9C schematically show wipes according to embodiments of thepresent invention.

FIG. 10 schematically shows a dry wipe according to an embodiment of thepresent invention.

FIG. 11 shows schematically a filter according to an embodiment of thepresent invention.

FIG. 12 shows schematically a carpet according to an embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION Definitions

A “trilobal shaped fibre” has a trilobal cross-sectional geometryincluding three lobes defined by three tips and made of a sheathmaterial, and a generally solid central core section running axiallythrough the fibre. Any of the trilobal shaped fibers used in any of theembodiments of the present invention may be staple or short-cut fibers,e.g. alone, in combinations or in blends. A trilobal fibre has a lobedcross-sectional geometry including a sheath having three lobes and hencedefined by three tips, and also a generally solid central core sectionrunning axially through the fibre having a similar shape to the sheath.Each outer side of the fibre (at least before thermal bonding)preferably defines a smoothly curved contour extending between each tipand a neighbouring tip, each side preferably including a concave regionlocated at an approximate midpoint between neighbouring tips. Howevertriangular and even convex curves can be useful for certainapplications. Hence, other shapes are included within the scope of thepresent invention, however in any shape it is preferred if there arethree four lobes presenting sheath material to the outside which has alower melting point than the core material, e.g. 10° C. difference.Preferably, each outer side of the fibre preferably defines a contourextending between each tip and a neighbouring tip, each such contour cancomprise any one of the following: a straight line, a concave shape or aconvex shape. In the case of the convex shape the convex shapepreferably does not extend out from the core such as to extend beyond aline drawn between two adjacent tips.

“Staple fibers” are fibers of limited length, e.g. 20 to 120 mm or up to300 mm. Staple fibers as used in embodiments of the present inventioncan be trilobal in cross-section.

“Bi-component staple trilobal fibers” according to any of theembodiments of the present invention can be crimped. Crimping ofbi-component staple trilobal fibers can exploit, for example, molecularweight and/or stereochemistry differences of each component or canexploit a differential in the orientation level across the fiberdiameter. Additionally, polymer additives like cross linkers orbranching agents can also be used to create a similar effect. Fibrecrimp is defined as the waviness of a fiber expressed as waves or crimpsper unit length (see for example ASTM D123) or, can be defined as thedifference in distance between two points on a fiber as it lies in in anunstretched condition and the same two points when the fiber isstraightened under specific tension, expressed as a percentage of theunstretched length (see for example ASTM D123).

“Short-cut fibers” as used with respect to any of the embodiments of thepresent invention are cut trilobal fibres of a length from 2 to 25 mmand are generally not crimped. Short-cut fibres as used in embodimentsof the present invention can also be bi-component trilobal short-cutfibres and can be used alone or in a blend, and can be processed withwet- or air laid technologies. Crimped short-cut fibers are lesspreferred but can have an inherently open nature, and can be processedin air-laid applications. They can have mechanical binding properties.They can be used in wipes, filtration, or absorbent hygiene products,for example.

A “nonwoven structure” which can be used with the present invention mayinclude trilobal staple optionally crimped fibres nonwovenmade byproviding cut fibres of several centimetres length, e.g. 20 to 120 mmlength or up to 300 mm length. These fibers can be put into bales,placed on a conveyor belt and dispersed, e.g. spread in a uniform web bya wetlaid, airlaid, or carding/crosslapping process. Nonwoven structurescan be made by a wetlaid process into mats, gauzes, scrims etc. Thenonwoven structure can be entangled by hydroentanglement or needlepunching in any of the embodiments of the present invention.

A nonwoven structure can also be made comprising bi-component trilobalshort-cut fibres of 2 to 25 mm in length, e.g. alone or in a blend.These fibers can be spread in a uniform web by an air-laid process, e.g.for making nonwoven structures for use in mats, gauzes, scrims; sheetsetc. The nonwoven structure can be entangled by hydroentanglement orneedle punching also in these embodiments of the present invention.

The term “needlepunched” means a nonwoven structure which isconsolidated by passing it though one or more needleboards carryingseveral thousands of needles that penetrate the nonwovens repeatedly,forming a mechanically entangled structure.

Test Methods

The following test methods are to be used.

Melting Point

Melting temperatures Tmelt (“melting point”) are determined according toISO 3146, e.g. on a DSC Q2000 instrument by TA Instruments. To erase thethermal history the samples can be first heated to 200° C. and kept at200° C. for a period of 3 minutes. The reported melting temperatures(“melting points”) are then determined with heating and cooling rates of20° C./min.

Dimensions: CEN/TS 14159

Total thickness mm: ISO 1765 whereby the tolerance is nominally ±15%

Total mass per unit area g/m²: ISO 8543 whereby the tolerance isnominally the mass ±15%

Fibre

Fibres as disclosed in this section can be used in the embodiments ofthe present invention of nonwovens or any embodiment of the presentinvention which includes a non-woven made with such fibres.

An embodiment of the present invention relates to manufacture of atrilobal bi-component staple or short-cut, optionally crimped, fibre. Abi-component staple or short-cut, optionally crimped, fibre comprises acore and a sheath, the sheath and the core have different meltingpoints, with the sheath melting point being lower than the core meltingpoint, the bi-component staple or short-cut, optionally crimped, fibrehaving an outer trilobal shaped cross-section. The sheath may be appliedas a conformal layer on the core. The bi-component staple or short-cut,optionally crimped, fibre has a triangular symmetry, with each lobe ofthe sheath material having an axis radiating out from the core, thethree axes of the trilobal shape being spaced angularly from each other,and the core has a triangular symmetry. The core of the bi-componentstaple or short-cut, optionally crimped, fibre can have a delta ortrilobal shaped cross-section conformal with the outer trilobal shapedcross-section. The sheath can be a co-polyester, a polyolefin, or aolefin copolymer and a polymer used for the core is a polyolefin, anolefin copolymer or polyester. The bi-component staple or short-cuttrilobal, optionally crimped, fibre can be manufactured with 45-55% byweight of the fibre being in the core and with 55-45% by weight of thefibre being in the sheath. However other weights are included within thescope of the invention such as the core having between 10% and 90% byweight of the fibre, and the sheath has between 90% and the 10% byweight of the fibre, the core having between 20% and 80% by weight ofthe fibre, and the sheath has between 80% and the 20% by weight of thefibre, the core having between 30% and 70% by weight of the fibre, andthe sheath has between 70% and the 30% by weight of the fibre, the corehaving between 40% and 60% by weight of the fibre, and the sheath hasbetween 60% and the 40% by weight of the fibre. The bi-component stapleor short-cut staple or short-cut trilobal, optionally crimped, fibre canhave a final titre of between 0.5 and 35 dtex, preferably between 0.9and 17 dtex.

In one preferred embodiment, the polymer used for the sheath ofbi-component staple or short-cut trilobal, optionally crimped, fibres isa polyolefin such as polypropylene, or polyethylene (LDPE, LLDPE orHDPE) or an olefin copolymer whereas the core is a polyolefin such aspolypropylene (PP) or an olefin copolymer such as a polypropylenecopolymer or polyester. In accordance with any of the embodiments of thepresent invention a or the polymer used for the sheath can comprise anon-grafted polyolefin component and a grafted polyolefin component,wherein the grafted polyolefin component is present in the sheath by atmost 50%, preferably at most 30% and most preferably at most 10%, byweight of the sheath. The grafting monomer may be ethylenicallyunsaturated carboxylic acids and ethylenically unsaturated carboxylicacid anhydrides, including derivatives of such acids, and mixturesthereof, and vinyl trialkoxy silanes. Examples of the acids andanhydrides, which may be mono, di- or polycarboxylic acids, are acrylicacid, methacrylic acid, maleic acid, fumaric acid, itaconic acid,crotonic acid, itaconic anhydride, maleic anhydride and substitutedmaleic anhydride e.g. dimethyl maleic anhydride or citraconic anhydride,nadic anhydride, nadic methyl anhydride and tetrahydro phthalicanhydride. Examples of derivatives of the unsaturated acids are salts,imides, amides and esters e.g. mono- and disodium maleate, acrylamide,maleimide, glycidyl methacrylate and diethyl fumarate. Examples of thevinyl trialkoxy silanes are vinyl trimethoxy silane and vinyl triethoxysilane.

The sheath can represent from 10 to 90% or 20-80%, or 30 to 70% or40-60%, or 45-55% by weight of the bi-component staple or short-cuttrilobal, optionally crimped, fibre. The core can represent theremaining amount of 0 to 10%, 80-20%, 70% to 30%, 60-40%, or 55-45% byweight of the bi-component staple or short-cut trilobal, optionallycrimped, fibre, respectively.

As an example of the manufacturing method, a trilobal staple orshort-cut, optionally crimped, fibre is made with a shaped polypropylenecore and with a polyethylene sheath which has a lower meltingtemperature than the core:

Polypropylene (PP)—HC12XB (by Polychim Industrie) with a Melt Flow Rate(MFR ASTM D1238: 230° C./2.16 Kg) of 25 g/10 min, density (ASTM1505)=0.90 g/cm³, heat deflection temperature (ASTM D648; 455 KPa) of105° C., heat deflection temperature (ASTM D648; 1820 KPa) of 56° C.,Vicat softening temperature (ASTM D1525-A; 9.81 N) of 154° C. and Vicatsoftening temperature (ASTM D1525-A; 49.05 N) of 95° C. was spun as atrilobal core.

Polyethylene (PE)—Aspun 6834 (by Dow Chemical company), with MFR (ISO1133: 190° C./2.16 Kg) of 17 g/10 min, density (ASTM D792) of 0.95 g/cm³and Melting Temperature (DSC Dow method) of 130° C. was spun over thecore to form a bi-component trilobal fibre. These fibres were then cutto form bi-component staple trilobal fibers in the range 20 to 120 mm orup to 300 mm or cut to form bi-component short-cut trilobal fibres of 2to 25 mm in length. The fibres can be optionally crimped.

Nonwoven Structures

Any of the embodiments of the present invention can be a nonwovenstructure comprising bi-component staple or short-cut, optionallycrimped, fibres comprising a core and a sheath, the sheath and the corehave different melting points, with the sheath melting point being lowerthan the core melting point, the bi-component fibre having an outertrilobal shaped cross-section.

Embodiments of the present invention can use through-air bondingtechnology in which a hot fluid (e.g. air) is forced through a preformedweb. If the temperature of the fluid is high enough, the polymer of thesheath of bi-component staple or short-cut, optionally crimped, fibrescan melt by forming bonds in which two or more fibres come into contact.Embodiments of the present invention can use thermal-bonding technology,in which a preformed web of fibres is passed between heated calenderrolls. Bonding occurs in the areas in which the fibres are pressed bythe heated rolls. On a smooth calender roll, bonding occurs whereverfibres cross each other while on an embossed calender roll, bondingoccurs primarily between the raised embossed areas. This results inbonding “points” or “spots”. In each of the mentioned processes, thebicomponent staple or short-cut, optionally crimped, fibres are heatedand, in the zones in which the melting occurs, form a bond that isconsolidated once the system is subsequently cooled. The nonwoven can beentangled by needle punching or hydro entanglement, for example.

Wipes and Hygiene Products

Any of the embodiments of the present invention can be a wipe or ahygiene product comprising a nonwoven structure made with bi-componentstaple or short-cut, optionally crimped, fibres comprising a core and asheath, the sheath and the core have different melting points, with thesheath melting point being lower than the core melting point, thebi-component fibre having an outer trilobal shaped cross-section. Asheath can be a conformal layer on a core. The cores of the bi-componentfibres can have a delta or trilobal shaped cross-section. The nonwovenstructure can have a basic weight between 12 gsm and 170 gsm. Thebi-component staple or short-cut fibre can have a triangular symmetry,with each lobe of the sheath material having axis radiating out from thecore, the three axes of the trilobal shape being spaced angularly fromeach other, and the core has a triangular symmetry. The core of thebi-component staple or short-cut fibres can have a delta or trilobalshaped cross-section conformal with the outer trilobal shapedcross-section. A polymer used for the sheath can be a co-polyester, apolyolefin, or an olefin copolymer and a polymer used for the core is apolyolefin, an olefin copolymer or a polyester or a co-polyester. Thesheath can have between 10-90% by weight of the fibre and the core canhave between 90-10%% by weight of the fibre. The sheath can be made frompolyethylene and can have between 45-55% by weight of the fibre andwherein the core can be made from polypropylene and can have between55-45% by weight of the fibre. The final titre can be between 0.5 and 35dtex, preferably between 0.9 and 17 dtex.

Embodiments of the present invention include gauzes, wipes, absorbentpads, hygiene products such as baby diapers, feminine liners, adultincontinence products, and the like. As shown schematically in FIG. 9Athese can include a top sheet (1) and/or a back sheet (2) made from orincluding a nonwoven structure with a weight range of 10 or 12 to 170 orfrom 14 to 48 gsm for example. These products can be made bycalender-thermal bonding technology. For example carded veils includingshaped bi-component staple, optionally crimped, fibres according to anyof the embodiments of the present invention can be subjected to theaction of pressure and temperature of a calender which process producesbonding spots of the bi-component staple trilobal, optionally crimped,fibre sheath material. Such products have the mechanical consistency ofa nonwoven. Alternatively, such products can be made by means ofair-through bonding technology using for example trilobal short-cutfibres. In this process carded veils including shaped bi-componentstaple or short-cut, optionally crimped, fibres according to any of theembodiments of the present invention are subjected to the action ofhot-air.

Shaped bi-component staple or short-cut trilobal, optionally crimped,fibres according to any of the embodiments of the present invention canbe used in the manufacture of Acquisition Distribution Layers (ADL).Typical weight ranges for ADL including shaped bi-component staple orshort-cut trilobal, optionally crimped, fibres according to any of theembodiments of the present invention lie between 10 and 170 gsm as afunction of the final product, e.g. baby diapers, feminine liners, adultincontinence products.

Cleaning wipes can be used for cleaning a variety of surfaces such askitchen surfaces, upholstery, curtains, furniture surfaces, and thelike.

As shown schematically in FIG. 9B a wipe can comprise a first liquidpermeable layer (3) and a second liquid permeable layer (4) joinedpossibly to a third liquid impermeable layer (5). The first layer (3)can include a nonwoven structure according to any of the embodiments ofthe present invention, e.g. comprising bi-component staple or short-cuttrilobal, optionally crimped, fibres. A cleaning composition can bereleasably absorbed into one or more of the first layer (3), the secondlayer (4) or a core, if present. As shown schematically in FIG. 9C acore (6) can be between the first layer (3) and the second layer (4).Within the core (6), a cleaning composition can be releasably absorbed.The first liquid permeable layer can provide for transmission ofcleaning composition from the core to a surface of the first layer.

Alternatively, an absorbing material such as a superabsorbent compoundcan held or encapsulated by one or more of the first layer (3), thesecond layer (4) or a core (6), if present. A core (6) can be betweenthe first layer and the second layer. Within the core, the absorbingmaterial can be held. The first liquid permeable layer can provide fortransmission of liquids from the surface of the first layer to the core.

The first layer can be attached to the core by using any technique knownin the art for joining webs of material, including, but not limited to,ultrasonic bonding, thermal bonding, thermo-welding, spray-gluing, forexample. Alternatively, the core can be encapsulated in a pocket formedby the first layer and the second layer without the core being attachedto the first layer and second layer.

As the first layer includes a nonwoven structure according to any of theembodiments of the present invention comprising bi-component trilobalstaple or short-cut, optionally crimped, fibres it possesses a softfeeling and is mechanically strong. The first layer may be a compositeor laminate made of a nonwoven structure according to any of theembodiments of the present invention another layer selected fromthermoplastic films, porous films, reticulated foams, natural fibresespecially cotton fibres.

The first layer can be hydrophobic, however the outer and/or innersurfaces of the first layer can be made hydrophilic by treatment with asurfactant which is substantially evenly and completely distributedthroughout the surface of the first layer.

The core can be a material that can releasably absorb a cleaningcomposition or can hold an absorbing material such as a superabsorbentmaterial. In practice, the voids within the core can act as a reservoirfor the cleaning composition or the absorbing material, the cleaningcomposition or the absorbing material being stored within thecapillaries within the core. The core can be a fibrous material in whichthe capillaries are provided by the interstitial spaces between thefibres of the core. The core can be an open-celled foam in which thecapillaries are provided by the interconnected pores within the foam. Aneconomical core can be provided by a nonwoven comprising polyolefinfibres according to any of the embodiments of the present invention.

The second layer can be liquid permeable. That is, the second layer canalso provide for transmission of liquid cleaning composition from a coreto a surface of the second layer or from the surface to the core.

The second layer can be made of a nonwoven comprising polyolefin fibresaccording to any of the embodiments of the present invention comprisingbi-component trilobal staple or short-cut, optionally crimped, fibresand hence is compliant and has a soft feeling.

The wipe can have an abrasive layer. The abrasive layer of the wipe canbe the second layer of the wipe. In such a wipe the first layercomprises a nonwoven structure according to any of the embodiments ofthe present invention comprising bi-component trilobal staple orshort-cut, optionally crimped, fibres and provides a soft and strongwiping surface and the abrasive layer can be on the side of the coreopposite to the first layer. For example, the wipe can have 3 layers, afirst layer, an abrasive layer being the second layer, and a coredisposed between the abrasive layer and first layer.

The second layer can be located between the abrasive layer and the core.A suitable abrasive layer can be manufactured from a wide range ofmaterials such as thermoplastic films, porous plastic films, reticulatedfoams, natural fibres of which cotton fibres are preferred, or anonwoven structure according to any of the embodiments of the presentinvention comprising bi-component trilobal staple or short-cut,optionally crimped fibres.

The use of the shaped bi-component trilobal staple or short-cut,optionally crimped, fibres according to any of the embodiments of thepresent invention provides improved bondability and can be exploited intop sheets, back sheets and ADL systems, to allow the use of loweramounts of the shaped bi-component trilobal staple or short-cut,optionally crimped, fibres in blends with other fibres by maintainingthe same mechanical consistency of the final nonwovens, to reduce thebase weight of the nonwoven and by maintaining good thickness levels andexcellent coverage effects. Moreover, the use of the shaped bi-componenttrilobal staple or short-cut, optionally crimped, fibres in thenonwovens for top sheets and back sheets can improve the bonding withthe polymer film (e.g. polyethylene) with which these systems are oftencoupled.

Wipes including shaped bi-component staple or short-cut, optionallycrimped, fibres according to any of the embodiments of the presentinvention can have weights in the range 10 (or 12) to 170, or 27 to 45gsm. They can be manufactured by using the calender-thermal bondingprocess or for example spunlace technology. In the spunlacing processthe mechanical consistency of the produced nonwovens including shapedbi-component staple or short-cut, optionally crimped, fibres accordingto any of the embodiments of the present invention is reached by themechanical bonding generated by hydro-entanglement, in which high-speedjets of water strike the web so that the fibres knot about one another.Alternatively needle punching can be used. A thermal-calendering processcan be used after the hydro-entanglement or needle punching in order tofix better the mechanical bonding and to improve the mechanicalcharacteristics of the nonwovens. The use of the shaped bi-componentstaple or short-cut trilobal, optionally crimped, fibre according to anyof the embodiments of the present invention in wipes can improve thecalendering process, and improved bulkiness, liquid behaviour and alsothe stability that can be realized by using lower temperatures.

For what concerns the shape of the shaped bi-component staple orshort-cut, optionally crimped, fibres according to any of theembodiments of the present invention, the sheath preferably has atrilobal shape and the core has a shape which has a symmetry similar tothat of the sheath, e.g. a delta shape or trilobal. Preferably both thecore and the sheath have a trilobal shape.

Dry Wipes

Any of the embodiments of the present invention can be a dry wipe or ahygiene product comprising a nonwoven structure made with bi-componentstaple or short-cut, optionally crimped, fibres comprising a core and asheath, the sheath and the core have different melting points, with thesheath melting point being lower than the core melting point, thebi-component fibre having an outer trilobal shaped cross-section. Asheath can be a conformal layer on a core. The cores of the bi-componentfibres can have a delta or trilobal shaped cross-section. The nonwovenstructure has a basic weight between 12 gsm and 170 gsm. Thebi-component staple or short-cut fibre can have a triangular symmetry,with each lobe of the sheath material having axis radiating out from thecore, the three axes of the trilobal shape being spaced angularly fromeach other, and the core has a triangular symmetry. The core of thebi-component staple or short-cut fibres has a delta or trilobal shapedcross-section conformal with the outer trilobal shaped cross-section. Apolymer used for the sheath can be a co-polyester, a polyolefin, or anolefin copolymer and a polymer used for the core is a polyolefin, anolefin copolymer or a polyester or a co-polyester. The sheath can havebetween 10-90% by weight of the fibre and the core can have between90-10%% by weight of the fibre. The sheath can be made from polyethyleneand can have between 45-55% by weight of the fibre and wherein the corecan be made from polypropylene and can have between 55-45% by weight ofthe fibre. The final titre can be between 0.5 and 35 dtex, preferablybetween 0.9 and 17 dtex.

As shown schematically in FIG. 10 a dry wipe according to an embodimentof the present invention comprises a nonwoven structure (7) according toany of the embodiments of the present invention having trilobalbi-component staple or short-cut, optionally crimped, fibres. Dry wipesaccording to embodiments of the present invention include shapedbi-component fibres according to any of the embodiments of the presentinvention which have been bonded to themselves or to mono-componentfibres. The shaped bi-component staple or short-cut optionally crimpedfibres permit good inter-fibre thermal bonding (e.g., in thru-air dryersor bonding ovens, through infra-red (IR) or radiofrequency (RF) heating,etc.) and are preferably trilobal in outer sheath shape. The shapedbi-component fibres provide softness.

The wipe may also include in one or more layers (8) of natural fibres,synthetic fibres, or mixtures of natural and synthetic fibres. Naturalfibres may include cellulosic fibres, such as wood pulp fibres, cotton,and rayon. Synthetic fibres may include fibres such as, polyolefins, forexample polyester and polypropylene fibres. The wipe may be capable ofbeing flushed in a toilet (i.e., it is “flushable”). For example, thethermal bonding treatment may be made in discrete zones so that the wipemay disintegrate into pieces sufficiently small, such that when beingtransported in the sewer system the pieces do not plug any element ofthe sewer system.

The wipe can be any size or shape that may be used for cleansing theskin, or providing other benefits when using or changing a hygienearticle. For example, in certain embodiments, the wipe may berectangular or circular. In certain embodiments, the wipe may be about25 square centimeters in size to about 50 square centimeters in size. Incertain other embodiments, the wipe may be between about 100 squarecentimeters in size to about 320 square centimeters) in size.

The wipe may be textured, patterned embossed, dyed, printed with ink,clear polymer or colored polymer, or combinations thereof. For example,the wipe may be printed or dyed to give a visual signal of an activeingredient. The wipe may be patterned by hydroforming or any othermethod known in the art.

Dry wipes including shaped bi-component staple or short-cut, optionallycrimped, fibres according to any of the embodiments of the presentinvention can have weights in the range 10 or 12 to 170 or 27-45 gsm.They can be manufactured by using the calender-thermal bonding processor for example spunlace technology. In the spunlacing process themechanical consistency of the produced nonwovens including shapedbi-component staple or short-cut, optionally crimped, fibres accordingto any of the embodiments of the present invention is reached by themechanical bonding generated by hydro-entanglement, in which high-speedjets of water strike the web so that the fibres knot about one another.Alternatively needle punching can be used. A thermal-calendering processcan be used after the hydro-entanglement or needle punching in order tofix better the mechanical bonding and to improve the mechanicalcharacteristics of the nonwovens. The use of the shaped bi-componenttrilobal staple or short-cut, optionally crimped, fibre according to anyof the embodiments of the present invention in wipes can improve thecalendering process, and improved bulkiness, liquid behaviour and alsothe stability that can be realized by using lower temperatures.

Filters

Any of the embodiments of the present invention can be a filtercomprising a nonwoven structure made with bi-component staple orshort-cut, optionally crimped, fibres comprising a core and a sheath,the sheath and the core have different melting points, with the sheathmelting point being lower than the core melting point, the bi-componentfibre having an outer trilobal shaped cross-section. A sheath can be aconformal layer on a core. The cores of the bi-component fibres can havea delta or trilobal shaped cross-section. The nonwoven structure has abasic weight between 12 gsm and 170 gsm. The bi-component staple orshort-cut fibre can have a triangular symmetry, with each lobe of thesheath material having axis radiating out from the core, the three axesof the trilobal shape being spaced angularly from each other, and thecore has a triangular symmetry. The core of the bi-component staple orshort-cut fibres has a delta or trilobal shaped cross-section conformalwith the outer trilobal shaped cross-section. A polymer used for thesheath can be a co-polyester, a polyolefin, or an olefin copolymer and apolymer used for the core is a polyolefin, an olefin copolymer or apolyester or a co-polyester. The sheath can have between 10-90% byweight of the fibre and the core can have between 90-10%% by weight ofthe fibre. The sheath can be made from polyethylene and can have between45-55% by weight of the fibre and wherein the core can be made frompolypropylene and can have between 55-45% by weight of the fibre. Thefinal titre can be between 0.5 and 35 dtex, preferably between 0.9 and17 dtex.

As shown schematically in FIG. 11 a filter can include a nonwoven layer(9) including shaped bi-component staple or short-cut trilobal,optionally crimped, fibres according to any of the embodiments of thepresent invention, have the properties of base weight, porosity, fibredenier, and other factors. These factors affect filter performance, suchas filtration efficiency, dust-holding capacity, air permeability, etc.Typically, there is a trade-off when designing these filters. With anincrease in filter efficiency there is usually a decrease in airpermeability, an increase in base weight, or some combination of both.

Filters including trilobal bi-component staple or short-cut, optionallycrimped, fibres according to any of the embodiments of the presentinvention can increase efficiency without increasing base weight orsacrificing permeability. Furthermore, nonwovens including bi-componentstaple or short-cut trilobal, optionally crimped, fibres according toany of the embodiments of the present invention can have improvedstiffness. The improvements can be realised in comparison with roundfibres.

Embodiments of the filters include shaped bi-component staple orshort-cut trilobal, optionally crimped, fibres according to any of theembodiments of the present invention which have been bonded tothemselves or to mono-component fibres. The shaped bi-component stapleor short-cut, optionally crimped, fibres permit good inter-fibre thermalbonding (e.g., in thru-air dryers or bonding ovens, through infra-red(IR) or radiofrequency (RF) heating, etc.) and are preferably trilobalin outer sheath shape. The shaped bi-component staple or short-cuttrilobal, optionally crimped, fibres increase filter efficiency withoutsignificantly adversely affecting permeability, as compared to nonwovenswith round fibres and equivalent base weights.

Nonwovens of shaped bi-component fibres including bi-component staple orshort-cut trilobal, optionally crimped, fibres according to any of theembodiments of the present invention either alone or mixed withmono-component fibres can achieve higher filter efficiencies, yet havesubstantially the same equivalent base weight and tensile strength asnonwovens made of round fibres. The nonwovens can be made by a dry laidprocessing or thru-air bonding applications. Shaped bi-component stapleor short-cut trilobal, optionally crimped, fibres according to any ofthe embodiments of the present invention can be thermoplastic staple orshort-cut, optionally crimped, fibres having a linear mass density ofbetween approximately 0.5 dtex and about 30 dtex. In some embodiments,mono-component fibres can be included and can be also thermoplasticstaple or short-cut, optionally crimped, fibres having a linear massdensity of between about 0.5 dtex and approximately 30 dtex. In variousdifferent embodiments, the shaped bi-component staple or short-cut,optionally crimped, fibres according to any of the embodiments of thepresent invention have an outer cross-sectional shape that is trilobal,with the core being delta shaped, or trilobal.

For some embodiments, the shaped bi-component staple or short-cuttrilobal, optionally crimped, fibres according to any of the embodimentsof the present invention comprise a core and a sheath, with the corehaving a higher melting point than the sheath. Thus, when heated, thesheath can become molten before the core. This permits the sheath of theshaped bi-component fibres to function as a bonding material, wherebythe core and the sheath should maintain structural integrity of theshaped fibres. Due to surface tension, a molten sheath may attempt tocircularise itself, i.e. to reduce its surface energy. By the core beingof a similar shape to the sheath the outer shape can be maintained aftermelting. After bonding the core and sheath of the shaped bi-componentstaple or short-cut trilobal, optionally crimped, fibres a networkstructure is provided with good tensile strength, stiffness, andporosity of the nonwoven. Preferably, the shaped bi-component staple orshort-cut trilobal, optionally crimped, fibres have a linear massdensity of between approximately 0.5 dtex and approximately 30 dtex.

The shaped cross-section of the bi-component staple or short-cut,optionally crimped, fibres according to any of the embodiments of thepresent invention increases the available surface area of these fibresduring filtration, thereby increasing the interface where thebi-component staple or short-cut, optionally crimped, fibres caninteract with diffusing particles during filtration. For example, atrilobal cross-sectional shape of the bi-component staple or short-cut,optionally crimped, fibres increases the tortuous length of thediffusion path, thus increasing filtration efficiency without increasingbase weight.

If addition, mono-component fibres which can be included in thenonwoven, need not be thermoplastic, since the mono-component fibres arenot the main bonding fibres. Thus, the mono-component fibres can beacrylic, glass, or other non-thermoplastic fibres. However,thermoplastic mono-component fibres may have advantages, such as, forexample, better bonding affinity to the shaped bi-component fibres. Forsome embodiments, polypropylene shaped mono-component fibres can be usedbecause polypropylene is the lowest density polymer for a given masslinear density (e.g. for a given dtex), thereby providing greatersurface area for a given dtex, as compared to other polymers. The lowerdensity, therefore, results in greater filtration ability to filter,better bonding characteristics, better ability to charge medium, andadvantageous triboelectric effects.

For some embodiments, it should be noted that in addition to shapedbi-component staple or short-cut trilobal, optionally crimped, fibresaccording to any of the embodiments of the present invention, shapedmono-component fibres can be used in conjunction with the shapedbi-component staple or short-cut, optionally crimped, fibres to increasethe surface area. For other embodiments, one can appreciate that shapedbi-component fibres can also be used to further increase surface area.It should also be noted that a polypropylene sheath with ahigher-melting-temperature polyester core can be used.

Carpets, Mats, Upholstery

Any of the embodiments of the present invention can be carpet, mat orrug, upholstery comprising a nonwoven structure made with bi-componentstaple or short-cut, optionally crimped, fibres comprising a core and asheath, the sheath and the core have different melting points, with thesheath melting point being lower than the core melting point, thebi-component fibre having an outer trilobal shaped cross-section. Asheath can be a conformal layer on a core. The cores of the bi-componentfibres can have a delta or trilobal shaped cross-section. The nonwovenstructure has a basic weight between 12 gsm and 170 gsm. Thebi-component staple or short-cut fibre can have a triangular symmetry,with each lobe of the sheath material having axis radiating out from thecore, the three axes of the trilobal shape being spaced angularly fromeach other, and the core has a triangular symmetry. The core of thebi-component staple or short-cut fibres has a delta or trilobal shapedcross-section conformal with the outer trilobal shaped cross-section. Apolymer used for the sheath can be a co-polyester, a polyolefin, or anolefin copolymer and a polymer used for the core is a polyolefin, anolefin copolymer or a polyester or a co-polyester. The sheath can havebetween 10-90% by weight of the fibre and the core can have between90-10%% by weight of the fibre. The sheath can be made from polyethyleneand can have between 45-55% by weight of the fibre and wherein the corecan be made from polypropylene and can have between 55-45% by weight ofthe fibre. The final titre can be between 0.5 and 35 dtex, preferablybetween 0.9 and 17 dtex.

As shown schematically in FIG. 12 a nonwoven structure (10) according toembodiments of the present invention can be used in carpets, rugs, matesand textile floor and wall covering in general. The nonwoven structuremay have a needlefelt structure. An advantage of event or exhibitioncarpet according to embodiments of the present invention is a reductionweight and/or cost, while keeping or improving performance such as goodabrasion resistance.

In accordance with embodiments of the present invention a floor coveringsuch as carpet rug or mat may include a facing layer including anonwoven structure according to any of the embodiments of the presentinvention comprising bi-component staple or short-cut trilobal,optionally crimped, fibres. The floor covering may include at least 50%by weight of trilobal staple or short-cut bi-component, optionallycrimped, fibres, and at least a partial thermal bonding of the fibres.

The trilobal bi-component staple or short-cut, optionally crimped, fibrecontent of the facing layer can be at least 60%, at least 70%, at least80% or at least 90% by weight of the total fibre content in the facinglayer, up to 100% by weight.

The bi-component trilobal staple or short-cut, optionally crimped,fibres of the facing layer are (at least partially) bound by a thermalbonding process. Further bonding methods may be applied in addition,e.g. by latex, or bonding powder. A backing layer (11) can be appliedbut is less preferred especially if it has a significant impact one theoverall manufacturing cost

Carpets, rugs or mats, upholstery, or floor or wall covering textiles ingeneral can include shaped bi-component staple or short-cut trilobal,optionally crimped, fibres according to any of the embodiments of thepresent invention can have weights in the range 100 to 1000 gsm,typically in the range 200 to 600 gsm or 150 to 350 gsm. In a preferredembodiment the weight of the nonwoven structure used as a top or facinglayer (base weight) is between 100 and 350 grams per square meter, forexample more preferred between 150-275 grams per square meter.

Fibre linear mass densities are preferably between 3.3 until 17 dtex,whereby there can be a mixture of linear mass densities of the fibrewithin one carpet. For example flat and structured carpet can be madewith a fibre of 8.9 dtex, white flat and structured carpet can have amixture of 3.3, 6.7 and 8.9 dtex. Fibres up to 17 dtex can be used forevent carpet with velour qualities, e.g. from 7 to 17 or from 9 to 17dtex.

Carpets according to embodiments of the present invention can bemanufactured by using the calender-thermal bonding process or forexample spunlace technology or needle punching. In the spunlacingprocess the mechanical consistency of the produced nonwovens includingshaped bi-component staple or short-cut, optionally crimped, fibresaccording to any of the embodiments of the present invention is reachedby the mechanical bonding generated by hydro-entanglement, in whichhigh-speed jets of water strike the web so that the fibres knot aboutone another. However, a thermal-calendering process can be used afterthe hydro-entanglement in order to fix better the mechanical bonding andto improve the mechanical characteristics of the nonwovens or needlepunching can be used. The use of the shaped bi-component staple orshort-cut trilobal, optionally crimped, fibre according to any of theembodiments of the present invention in textiles can improve thecalendering process, and improved bulkiness, liquid behaviour and alsothe stability that can be realized by using lower temperatures.

Carpets according to embodiments of the present invention have goodcoverage while having a low weight. Good coverage could be provided by ahigh weight dense fibre packing as this places as much polymer materialas possible to block transmitted light in any cross-section of thecarpet. So a compact fibre density would provide good coverage but wouldincrease weight. In accordance with embodiments of the present inventionthe lobed nature of the fibre creates “lobe tip-to-adjacent fibre” and“lobe-to-lobe” touching which spaces the fibres from each other. Thisform of packing allows a low weight with a high coverage in which airreplaces the polymer as much as possible. The tips of the lobespreferably have convex surfaces.

The facing layer can be printed, e.g. preferably digitally printed sothat the carpet can be customized to a requirement rather than stockinglarge quantities of pre-customised carpet.

Comparative Test Samples

Bundles of 36 filaments, bi-component (50 wt % PP/50 wt % PE) andmono-component (100 wt % PP), having a trilobal (as illustrated in FIGS.1 and 2) and round sections (as illustrated in FIG. 3), needed for thefollowing described evaluations, have been produced by using a spinningline. All these fibres have been obtained by maintaining the same rawmaterials, the same core/sheath ratio (50% core/50% sheath), the sameprocess conditions and the same final titre of 2,2 dtex (the dtex isdefined as the weight, expressed in grams, of 10.000 m of fibre).

The polymers used to produce these filaments were the PolypropyleneHomopolymer (PP) HC12XB (by POLYCHIM INDUSTRIE) and the Polyethylene(PE) Aspun 6834 (by DOW CHEMICAL COMPANY), having thermal and physicalcharacteristics as following detailed:

Polypropylene (PP)—HC12XB (by POLYCHIM INDUSTRIE):

-   -   MFR (ASTM D1238: 230° C./2.16 Kg)=25 g/10 min    -   Density (ASTM 1505)=0.90 g/cm³    -   Heat deflection temperature (ASTM D648; 455 KPa)=105° C.    -   Heat deflection temperature (ASTM D648; 1820 KPa)=56° C.    -   Vicat softening temperature (ASTM D1525-A; 9.81 N)=154° C.    -   Vicat softening temperature (ASTM D1525-A; 49.05 N)=95° C.

Polyethylene (PE)—Aspun 6834 (by DOW CHEMICAL COMPANY):

-   -   MFR (ISO 1133: 190° C./2.16 Kg)=17 g/10 min    -   Density (ASTM D792)=0.95 g/cm³    -   Melting Temperature (DSC Dow method)=130° C.

The produced fibres bundles systems are following listed together withthe adopted production settings:

PP/PE BICOMPONENT TRILOBAL FIBRES (BT)

-   -   Extruder A: Polypropylene (PP)    -   Zone 1=195° C./Zone 2=215° C./Zone 3=230° C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Extruder B: Polyethylene (PE)    -   Temperature profiles: Zone 1=195° C./Zone 2=215° C./Zone 3=230°        C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Total Throughput=0.4 g/h/min    -   Ratio Core [PP]=50%    -   Ratio Sheath [PE]=50%    -   Speed Denier Roll=1800 m/min    -   Speed Relax Roll=1800 m/min    -   Titre=2.2 dtex    -   Fibre shape=Trilobal

PP/PE BICOMPONENT ROUND FIBRES (BR)

-   -   Extruder A: Polypropylene (PP)    -   Zone 1=195° C./Zone 2=215° C./Zone 3=230° C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Extruder B: Polyethylene (PE)    -   Temperature profiles: Zone 1=195° C./Zone 2=215° C./Zone 3 =230°        C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Total Throughput=0.4 g/h/min    -   Ratio Core [PP]=50%    -   Ratio Sheath [PE]=50%    -   Speed Denier Roll=1800 m/min    -   Speed Relax Roll=1800 m/min    -   Titre=2.2 dtex    -   Fibre shape=Round

PP MONOCOMPONENT TRILOBAL FIBRES (MT)

-   -   Extruder A: Polypropylene (PP)    -   Zone 1=195° C./Zone 2=215° C./Zone 3=230° C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Extruder B: Polypropylene (PP)    -   Temperature profiles: Zone 1=195° C./Zone 2=215° C./Zone 3=230°        C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Total Throughput=0.4 g/h/min    -   Ratio Core [PP]=50%    -   Ratio Sheath [PE]=50%    -   Speed Denier Roll=1800 m/min    -   Speed Relax Roll=1800 m/min    -   Titre=2.2 dtex    -   Fibre shape=Trilobal

PP MONOCOMPONENT ROUND FIBRES (MR)

Extruder A: Polypropylene (PP)

-   -   Zone 1=195° C./Zone 2=215° C./Zone 3=230° C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Extruder B: Polypropylene (PP)    -   Temperature profiles: Zone 1=195° C./Zone 2=215° C./Zone 3=230°        C.    -   Distribution pipeline=235° C./Spin-head=230-235° C.    -   Total Throughput=0.4 g/h/min    -   Ratio Core [PP]=50%    -   Ratio Sheath [PE]=50%    -   Speed Denier Roll=1800 m/min    -   Speed Relax Roll=1800 m/min    -   Titre=2.2 dtex    -   Fibre shape=Round

Evaluation of the Bonding Properties of the Fibres

For the evaluation of the thermal-bondability of fibres, a nonwovenfabric is prepared by using the fibres to be tested by calendering theweb under controlled conditions. Subsequently, the tensions needed totear apart the nonwoven fabric, both in the direction parallel to andtransverse to the calendering direction, are measured. The tensionvalues determined in this way are an indirect measure of thethermo-welding capability of the fibres.

The numerical results, however, can be substantially influenced by thefinishing characteristics of the fibres such as crimping, surfacefinishing, thermosetting, etc., and by the homogeneity of distributionof the web entering the calender. In order to avoid these inconveniencesand obtain a direct evaluation of the thermo-bondability characteristicsof the fibres a method has been perfected as described in the EP0629720and EP0391438.

The tested specimens have been prepared by coupling 2 of the abovedescribed uncrimped fibre bundles (36 filament for each) abovedescribed, made up of fibres 30 cm long, by forming a unique bundle of72 filaments (around 158.4 dtex). The roving has been then twisted sixtytimes by means of a twist measuring device (Carderara Bossi S.p.A.) andthe two extremities are united, thus obtaining a product where the twohalves of the roving are entwined as in a rope. The bonding spots arethen carried out on the above described specimen by using a BruggelHSG-ETK thermo-welding equipment, operating at a plate temperature of150° C., and by using a clamping pressure of 300 N and 0.5 secondswelding times. A typical obtained bonding spot is illustrated in FIG. 4.

A dynamometer (Vibrodyn-Lenzing AG) is used to measure the average forcerequired to separate the two halves of the roving which constitute eachspecimen at the thermo-bonded point. The distance between the clamps ofthe dynamometer was of 10 mm and the cross head was set at a speed of 20mm/min by using the same configuration of the instrument illustrate inFIG. 5.

The results, expressed in centinewton (cN), were obtained by averagingout at least ten measurements, and represent the thermal-bondingcapacity of the tested systems.

During the execution of the tests, has surprisingly been observed howthe samples containing PP/PE Bi-component trilobal fibres exhibitedhigher debonding forces (FIG. 7) in comparison with the systems in whichthe bi-component filaments have a round cross-section shape (FIG. 6).These obtained results, summarized in the Table A (FIG. 8), are provingan unexpected improvement of the bondability properties of thebi-component fibres when their cross-section is trilobal. The PP/PEbi-component Trilobal fibres, with their proven improvedthermal-bondability, can be used for the production of nonwovens havinga higher mechanical strength, for reducing the nonwovens weights bymaintaining a good coverage levels or to increase the average thicknessof the nonwovens by maintaining equal weight.

1.-17. (canceled)
 18. A bi-component staple or short-cut fibrecomprising a core and a sheath, the sheath and the core have differentmelting points, with the sheath melting point being lower than the coremelting point, the bi-component fibre having an outer trilobal shapedcross-section.
 19. The bi-component staple or short-cut fibre accordingto claim 18, wherein the sheath is a conformal layer on a core.
 20. Thebi-component staple or short-cut fibre of claim 19 wherein the fibre hasa triangular symmetry, with each lobe of the sheath material having anaxis radiating out from the core, and three axes of the trilobal shapebeing spaced angularly from each other, and the core has a triangularsymmetry.
 21. The bi-component staple or short-cut fibre of claim 20wherein the core of the bi-component fibre has a delta or trilobalshaped cross-section conformal with the outer trilobal shapedcross-section.
 22. The bi-component staple or short-cut fibre of claim18 wherein a polymer used for the sheath is a co-polyester, apolyolefin, or an olefin copolymer and a polymer used for the core is apolyolefin, an olefin copolymer or a polyester or a co-polyester. 23.The bi-component staple or short-cut fibre of claim 18 wherein thesheath has between 10-90% by weight of the fibre and the core hasbetween 90-10% by weight of the fibre.
 24. The bi-component staple orshort-cut fibre of claim 18, wherein the sheath is made frompolyethylene and has between 30-70% by weight of the fibre and whereinthe core is made from polypropylene and has between 70-30% by weight ofthe fibre.
 25. The bi-component staple or short-cut fibre of claim 18,in which the final titre is between 0.5 and 35 dtex, preferably between0.9 and 17 dtex.
 26. A nonwoven structure produced by using bi-componentstaple or short-cut fibres as claimed in claim
 18. 27. The nonwovenstructure according to claim 26 wherein the staple or short-cut fibrehas a triangular symmetry, with each lobe of the sheath material havingan axis radiating out from the core, and three axes of the trilobalshape being spaced angularly from each other, and the core has atriangular symmetry.
 28. The nonwoven structure according to claim 26,wherein the nonwoven structure is produced by carded thermal bonding,carded air-through bonding, spun bond, or is melt blown.
 29. A nonwovenstructure having an entanglement of staple or short-cut fibres, thestaple or short-cut fibres comprising bi-component fibres thermallybonded to bi-component fibres or also thermally bonded to somemono-component fibres, the bi-component fibres comprising a core and asheath, the sheath and the core have different melting points, with thesheath melting point being lower than the core melting point, thebi-component fibres having an outer trilobal shaped cross-section. 30.The nonwoven structure according to claim 29, wherein each sheath is aconformal layer on a core.
 31. The nonwoven structure according to claim29, wherein the cores of the bi-component fibres have a delta ortrilobal shaped cross-section.
 32. The nonwoven structure of claim 26wherein the nonwoven structure has a basic weight between 12 gsm and 170gsm.
 33. An absorbent article comprising (i) a surface sheet comprisingthe nonwoven structure of claim 26, or (ii) a cover layer comprising thenonwoven structure, the absorbent article further comprising a liquidpermeable body-facing cover layer, a liquid impermeable garment-facingbarrier layer and an absorbent core between the cover layer and thebarrier layer.
 34. The absorbent articles according to claim 33, furthercomprising, beneath the surface sheet, an acquisition/transportationsheet and an absorbent sheet and a liquid-impermeable backing sheet. 35.A filter, a hygiene product, a carpet, a rug, a mat, upholstery, or drywipe or a wet wipe comprising the nonwoven structure according to claim26.
 36. The absorbent article according to claim 33 wherein the stapleor short-cut fibre has a triangular symmetry, with each lobe of thesheath material having axis radiating out from the core, and three axesof the trilobal shape being spaced angularly from each other, and thecore has a triangular symmetry.
 37. The absorbent article according toclaim 36, wherein the core of the bi-component fibre has a delta ortrilobal shaped cross-section conformal with the outer trilobal shapedcross-section.